Display assemblies having shelves for displaying articles or products are well known. Typically, such arrangements include a plurality of horizontal shelves which are spaced from one another vertically. However, conventional display units suffer from a number of disadvantages. For example, often it is desirable to display a sample product separately from other products so that the product can be readily identified as a sample. If a permanent sample shelf is provided, such a shelf is inconvenient if the display unit is later to be utilized for products in which no sample is provided. Also, conventional display units can be difficult to adapt to the space and positioning constraints which can vary greatly from location to location. Conventional display units can also be less than optimal with regard to their ability to change the appearance of the display, where it is desired to change the overall appearance of the display, or to make even minor changes such as the use or positioning of the sample holding flaps or sub-shelves.